Human very low density lipoproteins fractionated by gel filtration will be characterized by quasi-elastic light scattering to yield diffusion coefficients and in the ultracentrifuge at various densities to yield sedimentation coefficient distributions and buoyant densities. By combining these data, the relationships between molecular weight, sedimentation coefficient, and buoyant densities will be obtained. Both normal lipoproteins and lipoproteins isolated from patients with lipid transport diseases will be studied.